Fitted sheets are typically configured to cover a substantial portion of a mattress and engage the mattress to obviate undesired movement of the fitted sheet. Typically, fitted sheets are provided with at top panel, side panels extending from the edges of the top panel and elastic along all of the edges of the side panels or along the edges of two opposite side panels. The side panels are sized so that a portion of the side panels can be tucked underneath the mattress and held in place by the elastic.
Most fitted sheets are sized to match the dimensions of a twin-size mattress, double-size mattress, queen-size mattress or king-size mattress so that the side panels conform to the sides and corners of the mattress to enable a close-fitting engagement with the mattress. Because these fitted sheets are designed for a close-fit engagement with a selected size or type of mattress they do not fit well on mattresses of other sizes. Gusman in U.S. Pat. No. 4,703,530 discloses a fitted sheet that he says will fit a range of mattress sizes without undue wrinkling or bunching of the fabric. This sheet has elastic along the corner seams which is intended to gather the fabric is all directions beneath the mattress. To enable the sheet to fit all sizes of mattresses the sheet must contain enough fabric to cover the largest mattress. For that reason this sheet will be more expensive than most other fitted sheets.
Twin-size mattresses are sold in a standard size and an XL size. Both mattress sizes have the same width but the XL-size twin mattress is five inches longer, having a length of 80 inches compared to 75 inches for a standard-size twin mattress. The XL-size twin mattress is commonly used in college dormitory rooms while the twin beds in most homes are a standard length. Consequently, college students and their parents are required to purchase XL-size twin sheets for the bed in the college dormitory room. Because the XL-size twin sheets are longer than standard-size twin sheets the fitted XL-size twin sheet will not fit well on a standard-size twin mattress. Wrinkling and undue bunching occurs. Hence college students who live in a college dormitory must have one set of sheets for college and another set of twin-size sheets for home.
There is a need for one fitted sheet that can be used on both a standard-size twin mattress and on an XL-size twin mattress without undue wrinkling or bunching of the fabric on the standard-size twin mattress and without slipping off the XL-size twin mattress.